Expanded US income tax data: marginal tax rates for a given AGI and filing status in any year from 1913 to present and maximum and minimum individual and corporate income tax rates by US state—Blog post »

International health indicators: added data on dozens of key health indicators for all countries, including numbers of medical personnel and statistics on immunization, contraception, drinking water quality, and tobacco use

US Social Statistics

Expanded US housing data: added Case-Shiller index, number of houses, and aggregate home value by US metropolitan area, plus the ability to ask about where home prices are rising or falling in a particular region—Blog post »

Astronomy

Space weather: important extraterrestrial features of the solar system like sun spots, solar x-ray flux, and more; time series data for sunspots, solar x-ray flux, interplanetary magnetic field, and Kp-index—Blog post »

Sun path, sky maps, and local sidereal time: graphical representation of the daily path of the Sun, various location- and time- related facts about the Sun during rise/set, UV index forecast information, observatories, and local sidereal time—Blog post »

New astronomical formulas: determine the orbital velocity for an object around a center of known mass and with a known circular orbital radius; compute basic properties of telescopes, such as light gathering power and magnifying power

Ice ages and glaciations: data on 6 major ice ages, including temperature and CO2 trends for the current ice age, as well as regional names and type of glaciation and continental configuration for ancient ice ages

Sunburn: skin-type dependent time to sunburn calculations provided for any location and current conditions;
the time-dependence of the UV dose over the day and potentially applied sunscreen are properly taken into account

Physics

Harmonic oscillator: formulas for computing the amplitudes, phases, and time-evolution of undamped, damped, and forced harmonic oscillators and realizations of the oscillators through springs and pendula

Units and Measures

Upgrades to wire and steel gauges: mass, thermal, and electrical properties of given lengths of wire of a certain gauge and material; comparison of the size of wire gauge with other industrial measures in the system; thickness, tolerance, area density, and gamma radiation halving thickness for a given steel gauge

Knitting needle sizes: equivalent needle sizes in multiple systems and dimensions for both nominal size parameter inputs and actual diameters and comparison of sizes with other industrial measures in the system

Number theory enhancements: compute final digits of large integers; visualize modular arithmetic with clocks; compute common divisors and multiples; identify perfect numbers; compute digit sums in any base

Technology and Computer Systems

Frequency allocations: ITU/FCC allocations for a frequency given a
geographical location, classes of sounds (ultrasound, etc.),
and a small, selected list of animals that can hear particular sound ranges